You can use the yield keyword to hold and return the data to the caller. See below for an example.

Public static IEnumerable ExampleMethod(){            List li = new List();            foreach (int item in li)            {                if (item  3)                {                    li.Add(i);                }            }          //Instead of the above, you could use Yield like below           foreach (int item in ListCollection)            {                if (item  3) yield return item;            }}